Prevalence of Noncarious Cervical Lesions and Associated Factors After Orthodontic Treatment: A Long-Term Follow-Up

The study aimed to evaluate the long-term occurrence of noncarious cervical lesions (NCCLs) in adults previously treated with fixed orthodontic appliances, considering tooth type, gingival phenotype, and the quality and stability of orthodontic treatment outcomes.

This observational study included 41 adult patients with complete orthodontic records. Data were collected at three time points: T1, before orthodontic treatment; T2, immediately after removal of fixed appliances and placement of retainers; and T3, during a long-term follow-up visit. At T1 and T2, information was obtained from orthodontic records, plaster models, and intraoral photographs. At T3, patients underwent clinical examination and standardized intraoral photographs. The presence and number of NCCLs were assessed from photographs at the three time points. The Peer Assessment Rating (PAR) index was used to evaluate treatment outcomes and stability. Gingival phenotype and lower fixed retainer status were assessed at T3. Friedman's ANOVA was used for comparisons over time, and the Mann-Whitney test was used for comparisons according to retainer status and gingival phenotype, with a significance level of 5%.

The mean interval was 2.5 years between T1 and T2 and 6.5 years between T2 and T3. The PAR index decreased significantly from T1 to T2 and remained stable from T2 to T3. The prevalence of patients with NCCLs was 24.4% at T1, 29.3% at T2, and 39.0% at T3. The number of teeth with NCCLs did not differ significantly between T1 and T2 but was higher at T3 than at T1 (p = 0.020). Premolars and molars were the most affected teeth. Patients with a thick gingival phenotype had fewer teeth with NCCLs than those with a thin phenotype at T1 and T2, but this difference was not statistically significant at T3.

In this sample of adults previously treated with fixed orthodontic appliances, the frequency of NCCLs was higher at long-term follow-up, while orthodontic treatment outcomes remained stable according to the PAR index. Premolars and molars were the most frequently affected teeth. The findings should be interpreted cautiously because behavioral, biological, and clinical factors related to NCCLs were not assessed longitudinally.